Im stuck ! Please help !

Hi guys,

I am a Z-grade computer caveman, and thus this thing is happening to me:

Case:

- 4 years of no anti-virus/spyware protection.
- Virus hit rundll32 from system 32 folder
- Downloaded Avast and I was cool enough to press Delete All during the scan phase after restarting Window.
- Avast deleted ALOT of files in system32 folder.
- Rundll loads ton of Error windows saying missing file this and that, obviously a virus doing this cuz it re pop-up whether or not I close those windows like crazy. So, yeh, I deleted that rundll32 file => It caused my comp to not working properly at all.
- I downloaded a rundll32 from an unknown Khmer dude online (well, just came accross it on google and downloaded immediately )

Problem:
- After putting that rundll32 into system32 folder via Safe Mode, the comp LOOKs normal. However, there is a thing "Window Installer" attempts to run at start-up but it stucks there and keep saying "Installing.." I have to close it with Task Manager.
-When I tried to open a folder, not working, the comp crashed and the mouse turn into a hour glass. It just stands there looking at me, sad. Same with most of other Window's programs.
-Open games (WOW; S4 League etc...heavy ones) the launcher doesnt appear on my screen, but it does appear from Task Manager's Processes Tab.
-Obviously and fortunately, only firefox works normally.

Fix:
- I want to re-install a new XP Operation System to replace this messed-up one. But, I dont know how to. I went to google alot to find methods, but they are out of my league, because my DVD-Drive is dead, there is no floppy drive in my CPU, what could i do now ?

What do i have ?
- USB holes
- My sis's laptop which is using a cool Vista, but bleh, I want my XP.
- Window XP Server Pack2 CD
- Love for the comp that serving me for more than 4 years.
Btw, Im using a desktop.

There is a way to get things done...but first, need to know a few things.

What is the make and model of the computer that is broken.
Can you enter BIOS (set-up) to see if booting to an external device (usb) is supported.
Is their a hidden repair partition on the computer to restore the computer back or does it actually require that it be created from CD.

Do you have access to a USB external CD drive or storage drive that can be used to restore the computer

I was able to get the comp to run normally after spending a whole night researching. But, when I was so happy my comp somehow recovered, another one strike me again just 4 mins later.

I went to this site to watch movies www.phim88.co m (pls dont visit it) and the comp got infected with the virus called Spyware Protection 2009. I got that virus before and I remembered i deleted some files in the system32 folder and it stopped its action, so i went for a try once more

Well, now the comp cant even reach window,or Safe Mode, instead it's only showing this message:

Quote:

Windows could not start because the following file is missing or corrupt: \WINDOWS\system32\c_437.nls

You can attempt to repair this file by starting Windows Setup using the original Setup CD-ROM. Select 'r' at the first screen to start repair.

I have no idea what does "the first screen" supposed to be and as I reported at the above post; my CD-Rom is dead already.

I hope these info might give you some idea on what's going on with my comp. As the CD-ROM is dead, i dont know what to do anymore since I cant even enter Safe Mode; I really dont want to throw away the comp that has been serving me for whole 4 years. I promise I will buy some anti virus soft to protect it if I could restore it to normal through your help. Pls save Big Bill (my comp's name) >.<